diff --git a/modules/environments/home-assistant/default.nix b/modules/environments/home-assistant/default.nix
index e3e8fe4..fc77dba 100644
--- a/modules/environments/home-assistant/default.nix
+++ b/modules/environments/home-assistant/default.nix
@@ -24,6 +24,7 @@ in
       extraComponents = [
         "matter"
         "mobile_app"
+        "zha"
       ];
     };
     services.home-assistant.config = {
@@ -32,6 +33,9 @@ in
       mobile_app = {};
     };
 
+    # Allow the `hass` service user to open the ZBT-2 USB-CDC serial endpoint.
+    users.users.hass.extraGroups = [ "dialout" ];
+
     my.homepage.services = [
       {
         group = "Services";